An Optical Phased Array (OPA) is the specific use of spatial light modulators to steer laser beams, or aim sensors, by progressive phase modulation. Coherent laser systems, including optical communication systems, LADAR imaging systems, and infrared countermeasure (IRCM) systems, require fast pointing systems that permit random access scanning of the battlespace in order to minimize timeline overhead to point at targets of interest. Conformal, wide-field-of-view beam steering is a significant enabler of IRCM, laser communications, and LIDAR applications on tactical fixed-wing and rotary wing aircraft.
Current optical beam steering methods, most of which are based on simple mechanics, are too bulky, slow, or inaccurate. Optical phase arrays for non-mechanical laser beam steering applications are difficult to fabricate without grating lobes because the devices require spacing of waveguide elements that are less than λ/2. Existing non-mechanical pointing solutions suffer from small field of regard (FOR) and/or are limited in wavelength to the visible or short wave infrared (SWIR) bands.
Conventionally, beams of laser light are steered using lenses or mirrors. In order to steer a beam, the lenses or mirrors are moved by a motor. Existing mechanical pointing solutions suffer from large size, weight, and power requirements, low slew rates, high settle times, tight mechanical tolerances, and do not permit random access scanning. Pointing solutions that are conformal to aircraft skin are desired to reduce drag and radar cross section impact of laser systems. It is difficult to build near-hemispherical field of view with regard to mechanical pointing systems without projecting into the air stream.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.